Background and Rationale Osteosarcoma is the most common pediatric bone cancer in the United States. Due to advances in surgery and chemotherapy, cure rates for patients with localized disease approach 70%. However, multiple attempts at intensification of chemotherapy have not improved the survival rate. In addition, long-term survival for patients with metastatic disease is only 25%. These figures point to the need to develop new therapeutic regimens. A different treatment approach is to utilize inhibitors that target activated tyrosine kinases. Imatinib, which targets ABL and KIT, has been the paradigm for the success of such treatment. Patients with CML have activation of ABL due to a BCR-ABL translocation and patients with GIST have activation of KIT due to mutations. Both groups of patients have remarkable responses when treated with Imatinib. A similar approach to treat patients with osteosarcoma does not exist presently, because there has not been a systematic examination of mutations in tyrosine kinases Study Design Our goal is sequence every gene in osteosarcoma tumor samples. In preparation for this project, we have identified tumor specimens collected previously from patients previously treated at the NIH under Pediatric Oncology Branch protocols. Approval was granted from the Office of Human Subjects Research to perform this study. We isolated DNA and RNA and went on to determine the quality of these samples. At the same time a small part of the tumor was sent for sectioning and H+E slides were examined with a pediatric pathologist, verifying the presence of tumor and the diagnosis as osteosarcoma. 2010 Plans Members of Dr. Paul Meltzers laboratory will perform comparative genomic hybridization to determine the quality of the DNA that we prepared. Sequencing and analysis of the DNA will be performed in his laboratory. Results will be returned to us and we will then prepare for genetic and biological evaluation of the DNA changes to determine if they are relevant targets for further therapeutic evaluation.